From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755503AbYCYLCl (ORCPT ); Tue, 25 Mar 2008 07:02:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753821AbYCYLCb (ORCPT ); Tue, 25 Mar 2008 07:02:31 -0400 Received: from mail.mev.co.uk ([62.49.15.74]:46237 "EHLO mail.mev.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753772AbYCYLCa (ORCPT ); Tue, 25 Mar 2008 07:02:30 -0400 Message-ID: <47E8DBBE.4030607@mev.co.uk> Date: Tue, 25 Mar 2008 11:02:22 +0000 From: Ian Abbott User-Agent: Thunderbird 2.0.0.12 (X11/20080317) MIME-Version: 1.0 To: Rob Landley Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] Corrections to Documentation/rbtree.txt References: <47E282F5.6090703@mev.co.uk> <200803201339.18618.rob@landley.net> In-Reply-To: <200803201339.18618.rob@landley.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 25 Mar 2008 11:02:23.0303 (UTC) FILETIME=[B4048570:01C88E67] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20/03/08 18:39, Rob Landley wrote: > On Thursday 20 March 2008 10:29:57 Ian Abbott wrote: >> From: Ian Abbott >> >> The description of the rb_entry() macro in Documentation/rbtree.txt seems >> incorrect. This patch improves it (hopefully). Also I changed the example >> code to call the previous 'my_search()' example instead of an undefined >> 'mysearch()'. > > I have no objection to the patch (and the my_search thing seems like an > obvious typo), but is there a reason to prefer rb_entry() rather than > container_of()? If so, the rationale might be a good thing to add to the > documentation... I don't know the rationale, but all the code I can see uses rb_entry() and not container_of(). The only rationale I can think of is that it abstracts away from the nodes being embedded in the data a little bit. (But not by much - in particular, an implementation of rb trees that stored data in the node explicitly would only need a single parameter in its rb_entry() accessor. I like the approach taken in include/linux/elevator.h that uses the rb_entry() macro to create a specialized accessor macro (rb_entry_rq()) with a single parameter. -- -=( Ian Abbott @ MEV Ltd. E-mail: )=- -=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-